[Marlinman]

I've been reading all the different opinions on changing the AT fluid on the ZF 8HP and it seems most people are sub 100k when they discuss. I'm approaching 100k in the next few months and wanted to ask the group if anyone has bothered to change their AT fluid at this far of an interval AND if they are FBO, upgraded turbo, or not, etc. If so, do you now have tranny problems with slippage, shifting, etc. Any info or feedback is appreciated. I can't decide whether to leave it since I currently have no issues (knocks on wood) or just add it to the maintenance list for hitting 100K. thanks.

[IraHayes]

If you plan on keeping the car long-term, definitely change it. 100k seems to be the longest you’d want to wait. ZF recommends changing between 50 and 80 thousand miles, but I’m “hearing” on this and other forums that some BMW dealerships and Indy shops are recommending 100k, so you’re right at the cusp. If you are going to do it, I would do it soon.

[Marlinman]

Okay thank you, I'm ordering the kit from FCP euro as we speak.

[bavarianride]

Originally Posted by IraHayes

If you plan on keeping the car long-term, definitely change it. 100k seems to be the longest you’d want to wait. ZF recommends changing between 50 and 80 thousand miles, but I’m “hearing” on this and other forums that some BMW dealerships and Indy shops are recommending 100k, so you’re right at the cusp. If you are going to do it, I would do it soon.

"hearing", as in echo chambers from the a few posters?

The other thing heard recently from local mechanics that they saw E46/E39/E90/D60 with 150k+ miles and zero AT maintenance, and the AT still works fine. The new gen of ZF 8AT though can be more complicated than those previous gen trannies though.

[insanecoder]

Originally Posted by Marlinman

I've been reading all the different opinions on changing the AT fluid on the ZF 8HP and it seems most people are sub 100k when they discuss. I'm approaching 100k in the next few months and wanted to ask the group if anyone has bothered to change their AT fluid at this far of an interval AND if they are FBO, upgraded turbo, or not, etc. If so, do you now have tranny problems with slippage, shifting, etc. Any info or feedback is appreciated. I can't decide whether to leave it since I currently have no issues (knocks on wood) or just add it to the maintenance list for hitting 100K. thanks.

imo there may be some risk in doing so now
however regarding the intervals of transmission fluid changes
back in the day, I used to change mine every 15,000 miles or so
yea synthetics and all that but synthetics does not extend oil lifetime from 15,000 to never!

[CarlosC]

Originally Posted by Marlinman

I've been reading all the different opinions on changing the AT fluid on the ZF 8HP and it seems most people are sub 100k when they discuss. I'm approaching 100k in the next few months and wanted to ask the group if anyone has bothered to change their AT fluid at this far of an interval AND if they are FBO, upgraded turbo, or not, etc. If so, do you now have tranny problems with slippage, shifting, etc. Any info or feedback is appreciated. I can't decide whether to leave it since I currently have no issues (knocks on wood) or just add it to the maintenance list for hitting 100K. thanks.

I changed mine at around 100k...no issues whatsoever. Stock 2012 328i (F30).

[perryo91]

Originally Posted by insanecoder

imo there may be some risk in doing so now
however regarding the intervals of transmission fluid changes
back in the day, I used to change mine every 15,000 miles or so
yea synthetics and all that but synthetics does not extend oil lifetime from 15,000 to never!

What do you mean by risk?

Also back in the day you'd change tranny oil about every year?

[jh_f30]

Originally Posted by perryo91

What do you mean by risk?

Also back in the day you'd change tranny oil about every year?

There is debate about whether doing an ATF change on high mileage cars is a good idea. Has been known to cause slipping after the fact, but I guess the debate is whether or not ZF has the same potential issues.

[IraHayes]

Originally Posted by jh_f30

There is debate about whether doing an ATF change on high mileage cars is a good idea. Has been known to cause slipping after the fact, but I guess the debate is whether or not ZF has the same potential issues.

I have experienced this slipping myself. I changed the trans fluid on my old Jeep at about 160k. I started experiencing a little slippage after that. Not too bad, most others couldn't notice, but I could tell since I drove the car on the daily.

[jh_f30]

Originally Posted by IraHayes

I have experienced this slipping myself. I changed the trans fluid on my old Jeep at about 160k. I started experiencing a little slippage after that. Not too bad, most others couldn't notice, but I could tell since I drove the car on the daily.

Was that with a drain & fill or a flush?

[perryo91]

Originally Posted by IraHayes

I have experienced this slipping myself. I changed the trans fluid on my old Jeep at about 160k. I started experiencing a little slippage after that. Not too bad, most others couldn't notice, but I could tell since I drove the car on the daily.

Oko ok hang on lol, an old jeep trans is I think a little different than our ZF trans. I wouldnt start saying that they're related even post fluid change.

[jh_f30]

Originally Posted by perryo91

Oko ok hang on lol, an old jeep trans is I think a little different than our ZF trans. I wouldnt start saying that they're related even post fluid change.

Just Google "ATF change problems". Knowledge is power.

[Marlinman]

This is why I posted! in for info of guys changing at this high of mileage and experiencing slippage. Especially with the beating some cars have taken after mods/etc.

[perryo91]

Originally Posted by jh_f30

Just Google "ATF change problems". Knowledge is power.

All anecdotal my friend (and on 20 year old cars).

Wisdom is more powerful.

[jh_f30]

Originally Posted by perryo91

All anecdotal my friend (and on 20 year old cars).

Wisdom is more powerful.

True. Hence my point that "there is debate".

[Marlinman]

any other takers

[bobalis]

I emailed ZF a while ago about this and this is what the replied with:

Thanks for contacting us in regard to your 335i and transmission maintenance. There is a factory schedule included in your maintenance schedule, however it's basic and does not address driving style or climate only normal and severe driving. Severe can be classified as Stop and go city, aggressive driving, heavy loads or short trips. With these types of driving we recommend 60,000 miles. For light driving which would be driving several miles to fully heat the transmission or continuous highway driving we would recommend 80,000 miles. Also be sure to use either ZF Lifeguard Fluid 8 or BMW fluid. The software for ZF transmissions includes properties of the fluid and if an alternative fluid is used it may affect transmission adaptions and could cause a failsafe mode. Also be sure to use Genuine BMW or ZF pan assembly with filter as it is as important to remove any clutch material or other debris from the oil pan as it is to replace the fluid.

Now the SA I used to go to said that they recommend to never touch the ATF and that its a "lifetime fill". I even sent him this response and he still recommended against it. It is my inclination to follow the instructions from the manufacturer of the transmission, however, its ultimately your choice.

[switchman]

Originally Posted by bobalis

I emailed ZF a while ago about this and this is what the replied with:

Thanks for contacting us in regard to your 335i and transmission maintenance. There is a factory schedule included in your maintenance schedule, however it's basic and does not address driving style or climate only normal and severe driving. Severe can be classified as Stop and go city, aggressive driving, heavy loads or short trips. With these types of driving we recommend 60,000 miles. For light driving which would be driving several miles to fully heat the transmission or continuous highway driving we would recommend 80,000 miles. Also be sure to use either ZF Lifeguard Fluid 8 or BMW fluid. The software for ZF transmissions includes properties of the fluid and if an alternative fluid is used it may affect transmission adaptions and could cause a failsafe mode. Also be sure to use Genuine BMW or ZF pan assembly with filter as it is as important to remove any clutch material or other debris from the oil pan as it is to replace the fluid.

Now the SA I used to go to said that they recommend to never touch the ATF and that its a "lifetime fill". I even sent him this response and he still recommended against it. It is my inclination to follow the instructions from the manufacturer of the transmission, however, its ultimately your choice.

I had '03 e39 at 80k and '06 e53 at 100k drain , filter change and refill. Both cars drive and shifted ok with no issues.
E39 was sold and still being driven by my friend, e53 drives well till I sold it at 128k miles.

These have different ZF tranny but both uses same fluid.